LQ4 into a 3rd Gen/1972 Nova by frojoe

3 minute(s) of a 891 minute read

I'm on a work trip in Taiwan right now, which has given me plenty of time to look over Holley data logs and look at various parameters to get a grasp of what my new setup has been doing.

A curious thing I noticed was that my gigantic custom Garrett intercooler seems to only have 2.2psi (15kPa) pressure drop across it, and look how it cools that charge air!

The crosshairs are highlighting the moment of peak boost for this log, which is 9.4psi or 165MPa. It's overrun the target boost of 8psi, but it's also a quick spike so I don't think the boost control is nearly fine-tuned yet.

Dark green = pre-intercooler IAT
Purple = MAT, aka IAT measured right before the throttlebody

It's neat to see how the pre-IC IAT lags behind RPM a bit but spikes accordingly, and then the pre-TB IAT stays steadily low, and drops with speed (aka RPM). This log was from May so ambient was probably low to mid 60's Farenheit... neat to see that IAT going into the throttlebody is damn near ambient, and is not affected at all by the big spike in post-compressor IAT measured (dark green). There's almost a 40 degree delta on the IAT before & after the intercooler.. and the air exiting the turbo (103*F) wasn't even that hot to being with.

This tells me the intercooler is prettymuch doing as good a job as it possibly can... this is making me want to try blocking off part of the intercooler and seeing the affect. What I'd be curious is to block off the area of the oil cooler I originally wanted to run in front of the intercooler. I wonder if blocking that sectional area off would be a near approximation to having the airflow resistance of the oil cooler compounded by the slower air exiting the oil cooler also being warm.

7-11-2019

Here's a recap of the non-standard and standard sensors I have on the thing, and their locations:

Passenger side - hot side, pre-turbo:
- Exhaust gas temp thermocouple (half way between exhaust manifold & turbo)
- Exhaust gas pressure sensor (half way between exhaust manifold & turbo)

Passenger side - cold side:
- Charge air temperature sensor, pre-intercooler (at compressor outlet of passenger side turbo)
- Charge air pressure sensor, pre-intercooler (at compressor outlet of passenger side turbo)

Passenger side - hot side, post-turbo:
- WB02 sensor (~20" down from turbo on passenger downpipe)
- Plugged bung for future Exhaust Gas Temp sensor in downpipe (~18" down from turbo)
- Plugged bung for future Exhaust Gas Pressure sensor in downpipe (~18" down from turbo, to measure downpipe backpressure)

Other sensors:
- Charge air temperature sensor, post-intercooler (right before throttlebody, used for Holley IAT)
- Manifold absolute pressure sensor (front of intake manifold, used for Holley MAP)
- Dome pressure sensor (single sensor tee'd into both wastegate domes)
- Rad fan shroud pressure sensor (to measure under-shroud pressure vs speed with fans on & off, to see if I need to add rubber flaps to vent shroud pressure)